MONTREAL - A little knowledge turned out to be a dangerous thing for Dmitri Vitaliev's students.

The activists gathered at the headquarters of a Tunisian human rights organization two years ago to soak up Vitaliev's tech-savvy tips on sending secure e-mail and other safe computing practices.

"And after the training, two of them leaving the offices were beaten on the street," Vitaliev said. "Unfortunately, this is the kind of harassment that they face quite often."

Cyberspace is an emerging frontier in the fight for human rights, and firewalls and identity maskers are the new tools for dodging oppressive regimes.

Advocates of democracy and free speech routinely use websites and e-mail to spread their messages, prompting wary officials in China, North Korea, Burma and numerous other countries to clamp down on the digital domain.

Through electronic surveillance and outright censorship, governments are trying to assert control over the Internet.

The Russian-born Vitaliev, who recently moved to Montreal, has conducted training sessions in about two dozen countries -- from Guatemala to Zimbabwe -- to help human rights defenders feel more at ease about going online.

But it seems Big Brother is never far away.

During a seminar in Kazakhstan, the computer network came under attack. In Iran, authorities got wind of the session, forcing the trainers to clandestinely teach several small groups in hotel rooms.

"This affects these people in a very real way, and sometimes in a very dangerous way, so you have to be very careful," said Vitaliev.

For him, the strongarm tactics of authorities only confirm the need for better computer security.

Vitaliev launched a how-to book at the recent Computers, Freedom and Privacy conference in Montreal, an annual meeting that examines the impact of information technology on people's lives.

Digital Security & Privacy for Human Rights Defenders, published with the backing of the Irish group Front Line, uses simple language and illustrations to demystify subjects like password protection, encryption and backing up data.

Working with Front Line and the Amsterdam-based Tactical Technology Collective, Vitaliev has also helped distribute 1,900 copies of NGO-in-a-Box -- a disc loaded with an array of security software tools aimed at turning any activist with a laptop into a one-person non-governmental organization.

The software is available in English, French, Spanish, Russian, Arabic and Farsi.

"There is a spread of oppressive technology. There is a spread of oppressive legislation," Vitaliev said. "But we are also seeing some better tools being developed in our community to give people a chance."

There are plans for a global network of trainers who will be able to teach students in their own languages.

Devotees call it hacktivism, a blend of computer hacking and traditional activism.

The simplest way to describe it is "using technology to improve human rights," said Oxblood Ruffin, who helped set up Hacktivismo nine years ago. The group is an offshoot of the semi-legendary Cult of the Dead Cow, an underground computer group formed in 1984 in Lubbock, Tex.

It develops technologies that allow Internet users in countries like China and Iran to circumvent national firewalls, and provides technical and security advice to NGOs.

Hacktivists are quick to dissociate themselves from the digital vandals that roam cyberspace.

"Hacktivism is not defacing websites or breaking into computers," said Eric Grimm, a Michigan lawyer who has worked with Ruffin. "Quite frankly that sort of tactic is very ineffective."

Vitaliev dismisses suggestions his training sessions might unwittingly arm people bent on doing harm with tools to elude the law. He insists the techniques he teaches are relatively common and not overly sophisticated.

"I can assure you that hackers and terrorists use much better tools already."